Some sellers are holding their homes off the market, anticipating prices will rise even more over the next year as the newly minted Facebook millionaires begin spending their money, the Mercury reported.

The San Francisco housing market seems to be hot now as well, especially at the low end — about half the houses listed under $1 million draw multiple bids and go for more than their asking prices, based on data shared by real estate agents over the last few months.

Bloomberg notes that these bidding wars are happening in other tech hotbeds like Seattle and Washington, D.C., as buyers gain confidence and suck up unsold inventory. Nationwide, inventory was at its lowest level since 2007, with only 2.43 million homes listed in February.

But outside these hotbeds, demand is still weak. The nationwide Case-Schiller index showed home prices down 3.8% in January from the previous year, and orders for new homes dropped 8 percent in the quarter ending Feb. 29.